Assembly of 3-halooxindoles via interrupted semipinacol Rearrangement: Enabling concise total synthesis of CPC-1

In continuation of our research interest in oxidation of indoles, we further explore the direct oxidation of indoles to 3-halooxindoles promoted by the combination of NCS, H₂O, and NaIO₄, thereby suppressing the competitive semipinacol rearrangement reaction. This methodology was demonstrated to be a robust protocol mainly consisting of broad substrate scope and excellent functional compatibility, thus enabling the preparation of high added-value versatile building blocks susceptible to further functionalization. Additionally, synthesis of natural product CPC-1 from commercially available starting materials has also been achieved in four steps using this reaction as a key transformation.